Rory McIlroy knows more than anyone that there is no easy way to win a US Open, and especially so on a links like Shinnecock Hills which historically has played as one of the toughest examinations of all Major venues.If the Northern Irishman is to claim a second career win in the championship, then there remains no other option than to do it the hard way in chasing down midway leader Wyndham Clark who stood imperiously atop the 36-holes leaderboard on seven-under-par 133, four shots ahead of his closest pursuers.McIlroy lay further adrift, seven behind, after a roller-coaster ride of a second round on the hilly Long Island links: a second round 71 – which featured four birdies, three bogeys and a double bogey – contrived to cast him in the role of pursuer, but not without hope and especially so with the prospect of the course firming up over the weekend.“When you are chasing, it’s sort of counterintuitive,” claimed McIlroy, adding, “but, for me, [knowing] that everyone else in the field is going to make bogeys, if I can limit my mistakes and pick off a few birdies here and there, that’s really the strategy.”McIlroy, whose only US Open win came at Congressional in 2011 and who has finished runner-up twice in the last three years, also pointed to how Brooks Koepka made a weekend charge in winning in 2018 on the last occasion that the championship was held on this famous old links.Back then, Koepka trailed Dustin Johnson by five strokes before making a successful defence in claiming back-to-back US Opens.In McIlroy’s case, it would need to be an even bigger comeback of seven strokes.“If there’s a course where you feel like you still have a chance if you’re seven back going into the weekend like I am, it’s definitely this one,” insisted McIlroy, in tied-11th, who identified limiting mistakes as critical to his effort.McIlroy added: “It’s not as if you can go and chase on this golf course. You just got to play super solid and hit fairways and hit greens and take your chances when they present themselves. I feel like I’m playing well enough to pick off a few birdies here and there.”World number one Scottie Scheffler – needing only the US Open to follow McIlroy into the Grand Slam club – moved into the weekend on the same 140 mark as McIlroy, after the American added a 68 to his opening round 72.Clark held a four strokes lead through 36-holes over the quartet of Matt Fitzpatrick, Xander Schauffele, Sam Stevens and Tom Kim.